CP VIOLATION at B-factories A.Bondar (Budker INP,Novosibirsk) Measurements of large CPV in b c c s...

CP VIOLATION at B-factoriesA.Bondar (Budker INP,Novosibirsk)

Measurements of large CPV in bc c s modes

Search for New Physics: CPV in bs penguin modes

Measurement of CPV in B+–

See also Today A.Mihalyi “Recent results on the CKM angle α from BABAR”

New method of the measurement in BD0K based on Dalitz plot analysis of the three body D0KS+–decay

See also Today M. Legendre “Status and prospects for the measurement of angle γ ”

T. Gershon “Measurement of φ3 using B– to DK– with D to Ks π+π–”

DANE04 Frascati June 7, 2004

Coupling strength at decay vertex : gFVij

universal Fermi weak coupling : gF

Vij : quark-mixing matrix elements

CKM matrix : unitarity : Vji*Vjk=ik explicit parametrization (Wolfenstein) complex phase leads to different bu and td amplit

udes for quarks and anti-quarks.

V Vud Vus Vub

Vcd Vcs Vcb

Vtd Vts Vtb

1 2 2 3A i 1 2 2 2A

3A 1 i 2A 1

(4 )

CP0.2235±0.0033 A 0.81±0.08 |i| 0.36±0.09 |i| 0.79±0.19

The Weak Decays of Quarks

quark decay

gFVijij

W

quark decay

gFVij*i

j

W


The Unitarity Triangle

Using orthogonality relation

* *ub ud tb td* *cb cd c

* * *ub ud cb cd tb td

b cd

V V V V

V V V V

V V V V V Vi k :=1, = + + =0

+ 1

3

+ = 0

B0 B0

B0 D(*)B+ DK

B0 J/Ks

B0 Ks

B0 D(*)D(*)

*ub ud*cb cd

V V

V V

*tb td*cb cd

V V

V V


CKM CP phenomenology

CP violation arises from the interference of two amplitudes with different phases.

Mixing induced CP violation : Indirect CPV Decay amplitudes asymmetry: Direct CPV

Single CKM phase = unique source of CPV ? It is difficult for CKM CPV to explain the observed

matter/antimatter asymmetry in the universe. It is needed to search for Beyond SM !


)}]sin(

)cos({1[);(/||

tmS

tmAe

tfBPBt

CP

Time-dependent CP violation

If either S or is non-zero, B fCP has CP asymmetry.If either S or is non-zero, B fCP has CP asymmetry.

0

0

0

0

CP CPf

B

BB f

B

CPfA

CPfA

CPfA

CPfAmixing mixing

decay decay

0 0q = 1 = ( ) for tag-side B B

Mixing induced CPV param.

Direct CP violation param.


KEKB & BELLEBELLE detector

KEKB Collider

~350 scientists, 55 institutions3.5GeV e+ & 8GeV e Asymmetric Collider3km circumference, 11mrad crossing angleL= 1.3 x 1034 cm–2s–1 (world record)Ldt = 266 fb–1 @{Y(4S)+off(~10%)}

(140fb1 : 1.52 x 108 )

BB pairs


PEPII & BABAR

BABAR Detector

PEPII Collider

3GeV e+ & 9GeV e Asymmetric Collider

L= 0.92 x 1034 cm–2s–1 Ldt = 214 fb–1 @{Y(4S)+off(~10%)}

Cherenkov Detector (DIRC)

Silicon Vertex Tracker

Instrumented Flux Return

CsI(Tl) Calorimeter

Superconducting Coil (1.5T)

Drift Chamber

e- (9 GeV)

e+ (3 GeV)


e e+e: 8.0 GeVe+: 3.5 GeV

BCP

z

Btag

(4S) ~ 0.425

fCPfCP

z cB ~ 200 m

Flavor tagFlavor tag

4 steps toward the CP violation measurement

• Reconstruct B fCP decays

• Determine the flavor of Btag • Measure proper-time interval : t • Evaluate asymmetry from the obtained t

distributions

How to measure CP violation ?


tags)(poor

tags) (good

DCPV No 0.0411.007 ||

0.0280.0570.733sin2

scc

1

06.073.02sin 1

13.080.02sin 1

hep-ex/0308036

0.0490.736)2WA2003(sin

tmeasuremen precision a becoming Now

1

sin21 : bbccsccs BB140 fb ~152M pairs- 1

BaBar 81 fb-1: sin(2φ1) =0.741±0.067±0.033



cos21 from B

J/J/

Moriond04,

M.Verderi


cos21 from B

J/J/


Non-Standard-Model particles could appear in the

penguin loop, modifying rate and/or CP asymmetry

Non-Standard-Model particles could appear in the

penguin loop, modifying rate and/or CP asymmetry

In the SM, for pure bs penguin transition modes sin21eff = sin21(BJ/KS)


L = 108 fb-1L = 108 fb-1hep-ex/0406005


L = 111 fb-

1

L = 111 fb-

1

BELLE PRD 60, 012001(2004)

hep-ex/0406005


sin21 Summary

Points of B0 π+π–

decay sensitive to CKM angle 2

direct CP violation may also occur because of interference between

b u tree amplitude and

b d penguin amplitude

It’s very important to check the KM matrix by other measurements.

b ud

B0 dW+

d

B0b

dB0

duud

gt

0 = = (1)Amp( ) = T + P tb td*

ub ud

*V VbO

a V VB a b


)(

)(

0

0

3

3

2

3

3

|/|1

|/|1

),||)|(|)(

),||)|(|)(

i

ii

iii

iii

eTP

eTPe

ePeeTBA

ePeeTBAPT

PT

221

21

12

212

|/|cos)cos(|/|21

,/]sin)sin(|/|2[

,/]2sin|/|

cos)sin(|/|22[sin

TPTPR

RTPA

RTP

TPS

TP

Constraints on the CKM angle 2

4 parameters

|P/T| 0.15-0.45 (representative) Theory ~0.31 23.7 deg (Belle & BaBar combined)

Strong phasedifference

convention taken fromM.Gronau and J.L.RosnerPhys. Rev. D65, 093012 (2002)



sin22 : bbuuduud , B0

High Quality Events

Low Quality Events

L = 140 fb-1L = 140 fb-1

S

A

Significance

Feldman-Cousins Analysis

(5.2 Observation of CP violation

3.2 for A=0 and any S

Evidence for direct CP violation

3.3 for “superweak” case

hep-ex/0401029


History of A and S

Belle

BaBarThis resultBelle 140fb1

Difference still at ~2.0 levelDANE04 Frascati June 7, 2004

Constraint on 2 and |P/T|

Belle140fb1

12

3

|P/T| > 0.17[95.5% C.L. (2)]

2 (

deg.

) (deg.)

2 (

deg.

)321

90 ≤ 2 ≤ 146 (95.5% CL) |P/T| =0.3

|P/T|

|P|/(|T|+|P|)



measurement, BDD(*)0(*)0KK



ρ-ω interference

Doubly Cabibbosuppressed K*

Construct f as sum of known two-body resonances plus non-resonant term, fit to continuum D*-to-D-to-Kππ data.



L = 140 fb-1L = 140 fb-1

73 events 73 events

B+ D(*)0K+ fit result

r+=0.40±0.15, θ+=256±19°

r- =0.21±0.15, θ- = 71±37°

B+ D0K+ B+ D*0K+

r+=0.29±0.19, θ+=353±38°

r- =0.38±0.19, θ- =249±32°




Combined fit:


Conclusion

Belle and BaBar continue to refine their measurements of from ccs

modes.

Belle and BaBar continue to refine their measurements of from ccs

modes.

__

Both experiments are using their high-luminosity data samples to probe for new physics in rare B decays: over-constrain the sides

and angles of the Unitarity Triangle.

Both experiments are using their high-luminosity data samples to probe for new physics in rare B decays: over-constrain the sides

and angles of the Unitarity Triangle.

todaytoday this summerthis summer in two years?in two years??

140fb-1140fb-1 270fb-1270fb-1 >500fb-1>500fb-1


Conclusion

Many new/updated results utilizing ~230–280 fb-1 of data per experiment will be shown

this summer.

Watch this space!

CP eigenstates

category CP mode process CP(f) SM prediction

S A Penguin

charmonium

J/ KS f sin21 0 negligibl

e(2S) KS

C1 KS

C KS

J/ K*(KS0)

J/ KL

charmonium

J/ 0 f sin21eff yes

double charm

D(*)D(*) small yes

bs penguin

KS f sin21 small dominan

t’ KS

K+KKS

hh f sin22eff yes

b ccs

b ccd

b uud

b sqq

(f CP eigenvalue)

0

0



Continuous Injection

sin22 : bbuuduud

Time-dependent CP asymmetries in B0 π+π– -- the best way to access the CKM angle 2

0

0

| |/

( ) [1 { sin( )

cos( )}]

Bt

qd

d

eP t q S m t

A m t

2

2 2

2

1 2, ,

1 1

( )

( )M

i

ImA S

A B fe

A B f

= +1 for B0 tag 1 for B0 tag

direct CP asymmetry

t=z/(c)




L = 113 fb-1L = 113 fb-1

CP VIOLATION at B-factories A.Bondar (Budker INP,Novosibirsk) Measurements of large CPV in b c c s...

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